#include<iostream>
#include<cmath>
#include<cstdio>

using namespace std;

int max(int x,int y,int z)
{
	int m;
	if (x>y && x>z)
		m = x;
	else if (y>x && y>z)
		m = y;
	else m=z;
	
	return m;	
}
void chuli()
{
	int a,b,c;
	scanf("%d %d %d",&a,&b,&c) ;
	
	double x = ((double)max(a,b,c))/((double)(max(a+b,b,c)*max(a,b,b+c)));
	printf("%.2lf\n",x);	
}
int main()
{
	chuli();
	return 0;
}
